A web-based platform for computer simulation of seismic ground response Zhaohui Yang, Jinchi Lu, Ahmed Elgamal * Department of Structural Engineering, University of California at San Diego, La Jolla, CA 92093 0085, USA Received 2 June 2003; accepted 4 March 2004 Available online 13 April 2004 Abstract The Internet provides an open environment for more efficient development and utilization of engineering software. This article presents a generic web-based platform for conducting model-based numerical simulations online. The platform distributes pre- and post-processing components to the user computer, and only retains core computational functions on the server machine. Design of this platform addresses Internet-specific issues such as supports for multiple users, integration of various programming languages or modules on both client and server sides, and the concerns of Internet traffic/security. As an implementation of this platform, a web site is developed for online execution of a solid – fluid fully coupled nonlinear Finite Element code, to conduct simulations of seismic ground response and liquefaction effects. At this web site, users can select the soil composition and input seismic excitation from built-in material/motion libraries, or define their own material properties and/or input motions. The output interface allows graphical rendering of simulation results, animations, and automated report generation. All software packages employed in this work are well tested and documented freeware, and can be easily adapted for execution of other computational codes. q 2004 Elsevier Ltd. All rights reserved. Keywords: Internet computing; World Wide Web; Software engineering; Java; Graphical user interface; Liquefaction; Seismic response 1. Introduction The Internet has introduced a robust real time mechanism for communication and interaction. In the near future, development and deployment of the Next Generation Internet (http://www.ngi.gov/) will lay down the infrastruc- ture for a worldwide communication network that is even faster and broader than most of today’s local networks. Ultimately, computers, data storage systems, local net- works, and other resources will be connected by the Internet as a single massive system (http://www.npaci.edu/teragrid/). These advances in communication infrastructure/hard- ware have allowed computer applications to be divided into components and distributed effectively over the Internet [1,2]. Today, most web-based computer programs leave user-interfacing tasks on the user (client) computers, and retain core processing functions on the server machine [3–6]. The interaction between users and central processing machines is accomplished through the client–server communication protocol of the World Wide Web (WWW), a standard software interface overlying the Internet infrastructure. As the Next Generation Internet matures, even the core computations can be further parallelized and distributed over the Internet [6,7]. Thus, technologies developed for high performance computing within a local network or inside a supercomputer can be extended to the Internet environment. It is also anticipated that by then, Internet-enabled real time computation and visualization will become commonplace so that user intervention (input interface), computation, and visualization (output interface) all occur concurrently with negligible time delay. Although relatively scarce, applications of Internet- enabled techniques to Finite Element (FE) computer simulations are fairly straightforward [8]. A typical FE simulation involves three main phases: (1) input phase: defining the FE model, (2) computation phase: executing the FE code, and (3) output phase: viewing/analyzing compu- tational results and writing a report. In the WWW environment, it is logical to distribute the phases 1 and 3 (i.e. user interfaces) to the client-side as shown in Fig. 1. This article describes the framework of a generic web- based computational platform for conducting model-based simulations on line, taking advantages of well-established web programming tools. The design of this platform takes 0965-9978/$ - see front matter q 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.advengsoft.2004.03.002 Advances in Engineering Software 35 (2004) 249–259 www.elsevier.com/locate/advengsoft * Corresponding author. Tel.: þ 1-858-822-1075; fax: þ1-858-822-2260. E-mail address: elgamal@uscd.edu (A. Elgamal).